Circuit breaker



p 1945- J. M. CUNNINGHAM 2,384,802

cmcurr BREAKER Filed May 27, 1943 Fig! FIG-3.2

' INVENTOR. c/4MES M CUA/Al/A/GHAM H18 A TI'ORNEK Patented Sept. 18, 1945 James M.

Cunningham, Endicott, N. 1., alsignor to International Business Machines Corpora- %on,' New York, N. Y., a corporation of New ork Application May 2 1, 194:. Serial No. 488,714

2 Claims.

This invention relates to circuit breakers and more particularly to cam operated contacts for making and breaking an electrical circuit.

The general object of the instant invention re- I sides in the provision of improved cam means for'operating electrical contacts according to selectively adjustable timing requirements.

More specifically, it is an object to provide a rotatable member with a pair of novel cam elements universally adjustable to enable one element to close the contacts at any point in a cycle of rotation and the other element to reopen the contacts at any other point in the cycle.

A still further object is to provide novel contact blade shifting mechanism intermediate an operating cam and the contact blade, which mechanism comprises a resiliently telescopingsleeve and plunger which effect a positive con-- trol over the opening and closing of the contacts, thereby minimizing arcing conditions.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawing, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawing:

Fig. 1 is an assembly view of the circuit breakalong lines 22 of Fig. 1.

Fig. 3 is a view similar to Fig. 1 with parts in operated position.

. Referring to the drawing, It represents a supporting frame in which is joumaled a shaft II. The shaft is arranged to be driven in a clockwise direction as viewed in Fig. 1 by any suitable power means (not shown). Fastened to the shaft in a predetermined relationship by means of a set screw I2 i a circuit closing cam l3, and on the hub thereof is carried an unlatching member I4 which is held in position on the hub by a headed screw it which extends through aslot it in the member. The hub of cam 12 is provided with four tapped holes spaced 90 apart, so that member I may be initially adjusted through the insertion of screw it in any of the four holes. The set screw 12 will, of course, be inserted in one of the three other positions. The slot, iii in member It extends for 90 so that with screw it in any hole the member It may be rotated, alter screw I5 By. the described construction, it is apparent therefore that cam 13 and member H may be given any relative relationship so that a given point on each will be any angular distance apart.

Located above shaft ii is a plunger i1 having a head It lying in the path 01' cam II, which head is engaged by the cam and elevated thereby. The

plunger I1 is slidable in a sleeve II which is freely slidable in a suitable bore in abracket 2. of insulating material. A spring 2| acts. to urge plunger I1 downward within sleeve It and a shoulder 22 acts as a limit stop for such downward movement, while a plate 28 acts as a limit stop for the downward position of both sleeve and plunger.

The upper end of sleeve I9 is provided with a plug 26 above which is positioned the contact 25 carried by resilient blade 2' for cooperation with fixed contact 21.

In the operation of the device, as the cam l3 rotates, it engages head ll and rapidly elevates plunger l1 against the action of spring 2i, compressing the spring and causing it to act against shoulder 22 to elevate sleeve It and plug 24 against blade 28. This results in closure of the contacts 25, 21. The transmission of power from cam I3 is accordingly through spring 2| which overcomes the resiliency of blade 28 and exerts a positive closing action on contacts 25, 21 and prevents contact 25 from bouncing away from contact 21, thereby minimizing arcing condition.

Pivoted at 29 on bracket 20 is a lever 22 which is normally urged clockwise about its pivot by a compression spring Ill, so that when head It is elevated by cam I3 latching edge 31 of lever 32 snaps under an edge 32 of head I! to hold the I ance for latching edge 33 to swing into latching has been loosened, to any rotative position with- I position, after which the head will move down slightly to seat itself on the latch. This, however, will not disturb the engagement between contacts 25 and 21 as spring 2| will permit the necessary flexibility to enable head It to make the slight descent without accompany s downward movement 01' sleeve l8.

Bracket 20 is secured to frame III by a bolt II extending through an elongated hole a in the frame, so that the entire bracket 20 may be adjusted slightly in a vertical direction to obtain the necessary clearance in the stroke of head ll. After the contacts have been closed by. cm I! and latched by lever 32, member I will strike a depending arm 31 to rock lever 82 counterclockwise to release head II whereupon spring 2| will or break is adjusted by positioning of cam ii on shaft Ii.

Further, there is provided a positive closing action in which spring 2i exerts the initial closin: force to bring contacts 25 and 11' together and thereafter continues to'exert substantially the same pressure to maintain the contacts in circuit closing engagement.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a single modification, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. An electrical circuit controller comprising a support, a stationary contact mounted on the support, a movable spring member having a contact engageable with the stationary contact to make an electrical circuit, said spring member normally biasing its contact away from the stationary contact, a sleeve mounted for reciprocation in said support for engaging and moving said spring member to contact closing position, a plunger 'slidably mounted within said sleeve, a spring within the sleeve for transmitting movement oi the lunger to the sleeve, a cam for moving the plunger, said movement of the plunger causing corresponding movement oi the sleeve through said spring to eiiect closure of the contacts, and a latch for engaging and holding said plunger in its moved position whereby the spring exerts a continuing force to maintain the contacts closed.

2. An electrical circuit controller comprising a support, a stationary contact mounted on the support, a movable spring member having a contact engageable with the stationary contact to make an electrical circuit, said spring member normally biasing its contact away from the stationary contact, a sleeve mounted for reciprocation in said support for engaging and moving said spring member to contact closing position, a plunger slidably mounted within said sleeve, a spring within the sleeve for transmitting movement of the plunger to the sleeve, a rotating cam for effecting a momentary movement 01 the plunger at a point in the rotation of the cam, said movement of the plunger causing corresponding movement of the sleeve through said spring to eilect closure of the contacts, a latch for engaging and holding said plunger in its moved position whereby the spring exerts a continuing force to maintain the contacts closed, and a member adiustably secured to said cam for engaging said latch at another point in the rotation of the cam to release the plunger whereby said spring and contact spring member will effect reopening of the contacts.

JAMES M. CUNNINGHAM. 

